Using DNA sequencing, study says dogs evolved
from European wolf
By Los Angeles Times, adapted by Newsela staff
Nov. 22, 2013
Grade level: 7
LOS ANGELES – Since the time of Charles Darwin, the father of evolution, scientists have
argued over the origin of domesticated dogs.
But recently, this one has become a major dogfight.
Some experts believe our ancestors in the Middle East and elsewhere were drawn to small, furry
wolf pups. They took in the pups as novelties. Other experts say they were raised as a source of
meat in early agricultural societies in Asia.
Yet another theory says that bands of hunters used the early dogs as helpers. This was long
before people ever figured out how to domesticate goats and sheep. Goats and sheep were the
first species tamed for agriculture.
Prehistoric Wolf Followed Hunters
Now, thanks to faster and cheaper DNA sequencing technology, the argument over what sparked
the Big Bark may finally be solved. DNA sequencing gives information about the exact genetic
structure of a creature and helps scientists trace how a species evolved.
According to a recent study in the journal Science, evolutionary biologists have concluded that
dogs were first domesticated most likely in Ice Age Europe 18,800 to 32,100 years ago. That's
much earlier, and much farther north, than previously believed. The discovery came after
biologists analyzed the mitochondrial DNA of 18 ancient dogs and wolves. They then compared
this with the mitochondrial DNA of modern dogs and wolves. Mitochondria are the tiny parts of
a cell that make energy.
The study's authors wrote that dogs evolved from a now extinct species of European wolf. This
wolf species, which died out long ago, followed bands of humans hunting woolly mammoths and
other large animals.
Initially, the wolves sought out dead animals and scraps of meat left behind by the hunters. Over
time the wolves began to hang around people.
People probably kept their distance from wolves at first, since the wolves were large and
aggressive, said Robert Wayne. He is an evolutionary biologist at the University of California,
Los Angeles. Evolutionary biologists study how life evolved on earth from simple life forms to
much more complex ones. Wayne is the study's main author.
Eventually, though, wolves entered the human community. They may have helped hunters locate
prey or kept other animals from getting in the way of the hunt, Wayne said.
Domesticated dogs spread. However, the European wolf that got the ball rolling left no living
descendants other than dogs.
Dog Evolution Hard To Trace
Modern day wolves are not the ancestor of dogs, said Wayne.
Until recently, many archaeologists and biologists believed that dogs were domesticated less
than 13,000 years ago, either in eastern Asia or the Middle East. One key find was a burial site in
Israel. It contained the 12,000-year-old skeleton of an elderly man cradling a puppy. This shows
the unique bond between dogs and humans.
Tracing the exact path of dog evolution has been extremely difficult. Ancient dog bones are hard
to tell apart from wolf bones. Frequent interbreeding between dogs and wolves further
complicates matters.
In fact, Charles Darwin, who died in 1882, believed that the huge variety of dog breeds meant
that dogs must have had more than one ancestor. Genetic researchers today say this probably is
not the case. They think domesticated dogs evolved from one ancestor, in one region.
"On some levels, understanding the geographic origins of dogs is definitely more difficult than
studying humans," said Greger Larson. He is a bioarchaeologist at Britain's Durham University.
Bioarchaeologists study animal bones from archaeological sites.
Larson said Wayne and the other authors had "significantly advanced" the debate on
domestication.
"I really like this paper," Larson said. The origin of dogs has been hard to pin down. "There have
always been crazy ideas about the process and the location."
Barking Up The Wrong Tree?
There are those, however, who argue that Wayne is barking up the wrong genetic tree.
Peter Savolainen is a professor of evolutionary genetics at Sweden's Royal Institute of
Technology. He said there is evidence that dogs were first domesticated in China, probably as a
source of food.
Savolainen pointed out that Wayne and his co-authors published a paper in 2010 citing the
Middle East as the origin of domestic dog. They have now abandoned this view.
The study's authors said they hoped to confirm their findings with additional testing of genetic
material from ancient cells. This is expected to provide more information.
In the meantime, experts are thinking about this latest theory and why scientists feel so strongly
about it.
"People make up tremendously elaborate stories about the origin of our own species based on a
few fossil remains here and there," said James Serpell. He is a professor at the University of
Pennsylvania. "I guess we're doing the same thing now to our dogs. We view them as members
of our families and we want to know where they came from and how this relationship came
about."
Lexile: 1100
FK: 9.2